Civil rights groups say the restrictions amounts to an attack on voting rights on a level not seen since segregation. Photograph: Tim Sloan/AFP/Getty Images

In Washington, conventional wisdom is everything. It's the driver of perceptions, and often of self-fulfilling political prophecies. That's why you might notice a guarded confidence amongst the Obama campaign these past few weeks: generally speaking, most realistic experts predict a victory for the president in this November's election.

This perception is reinforced by current polling, some of the most recent being published by Quinnipiac University, the New York Times and CBS News, giving President Obama an edge over Romney in key states like Ohio, Pennsylvania and Florida. Certainly, it will be a tight race, but by any realistic standard, the money is on Obama to pull out a victory, even narrowly.

But it's exactly the likely closeness of the race that may turn Washington's conventional wisdom on its head on election day. That's because, until relatively recently, political experts and journalists have been oblivious to a widespread and pernicious phenomenon occurring in many critical swing states – one that, unless checked, could erase Obama's electoral edge.

This phenomenon takes the form of a spate of new voter laws: efforts by Republican governors and Republican-controlled state legislatures to pass restrictive new voting rules just in time for election day. As a result, at least 5 million Americans could essentially lose their right to vote, according to the non-partisan Brennan Center in New York.

It's no surprise that these laws are almost uniformly designed to disenfranchise young people and minorities – the very demographics that make up part of Obama's base. And 5 million votes flagrantly stolen from the Democrats, especially in the swing states where Obama currently has the edge, could easily spell a Romney victory.

The Republican strategy here is simply too blatant to be believed, hence the relatively muted press coverage on the issue. Indeed, while Republican lawmakers have been busy undermining the basic rights of Americans for months now, it was not until recent weeks that the New York Times and Washington Post started paying attention.

As well they should, because it's no exaggeration to say that the results of these partisan tactics could make the Floridian recount of 2000 look like a minor political spat. We're looking at an election doomsday scenario that could eclipse any political scandal in American history.

Hyperbole? Not when you examine the new laws more closely. The legislation being passed by Republicans across the country takes various forms, all designed to stop likely Obama voters casting ballots.

The most common tactic is to heavily restrict the types of identification required at polling stations. In Pennsylvania, for example, that means requiring all voters to present very limited types of ID only available from the state's department of transportation. Since many inner-city voters don't drive, or many young voters have out-of-state driver's licenses, these likely Obama voters will all be stopped dead in their tracks before they reach the polling booth. The problem is so severe that the state of Pennsylvania itself has admitted that nearly 10% of voters do not have the required identification. In Philadelphia, an Obama stronghold, that figure is closer to 20%. Attorney General Eric Holder summed it up perfectly when he called these voter ID measures the equivalent of a "poll tax", at the NAACP summit in July.

In Florida, where history proves that less than 1,000 votes can swing a national election, the efforts to stop minorities and the poor from voting are not just limited to new voter identification laws. In fact, voter registration drives have been banned, and early voting, thought to favor Democrats, has been significantly curtailed. Even more worrying is Governor Rick Scott's attempt simply to remove Obama voters from the election rolls. In May, Scott ordered a purge of his state's voter lists, based on drivers' license records, which he acknowledged to be deeply flawed.

As a result, the state's division of elections initially found a mind-boggling 180,000 "ineligible voters" by performing a search of a computer database with inaccurate information. Yet, the purge goes on: the Miami Herald found that 58% of the people in a sample of 2,700 "ineligible" voters were Hispanic, and 14% were black. Whites and Republicans were least likely to be barred from voting. Even a second world war veteran was told he was not a citizen and so to stay away from the voting booth.

Of course, Republicans justify their efforts to suppress the vote by arguing that they're simply preventing illegal voting. That sounds entirely fair – until you consider that the proven occurrence of voter fraud is almost non-existent. In fact, not a single person has ever been prosecuted for voting illegally. Yet, the public seems ambivalent about voter ID laws, which is why similar dirty tricks continue, taking various forms in other competitive states such as Virginia, New Hampshire, Ohio, Wisconsin and North Carolina.

Luckily, progressive groups and the federal government are pushing back. In Pennsylvania, groups like the Advancement Project and the ACLU have filed suit on behalf of 38 plaintiffs, challenging the constitutionality of the new laws in state courts. The Advancement Project is also intervening in Wisconsin, fighting the fact that 78% of young African-American men lack the appropriate ID to vote, for example. The US department of justice is also intervening in Pennsylvania and other states, questioning whether new laws disproportionately discriminate against minorities. And the Obama campaign is acutely aware of the danger, with dozens of staffers in the campaign headquarters and out in the field monitoring daily developments in every critical state.

These counter-efforts are critical, yet the fear among Democrats is that they may not be sufficient to stop the new laws taking effect before the election. That is a significant danger, not only to the legitimacy of the results of the presidential race, but for the very core of America's democratic process. And, of course, it highlights the need for uniform standards across the country that guarantee free and fair elections.